Many of the current procedures for the treatment of cancer are disruptive and cause damage to healthy tissue. Two such procedures include resection of the tumor and hyperthermia treatment of the tumor. In a resection procedure, the physician must be careful not to cut the tumor in a manner that creates seeding of the tumor and thereby results in metastasis. In a hyperthermia procedure, the extent of localization of the heat is generally poor, resulting in damage to healthy tissue in the vicinity of the treatment site.
Ablation of cellular tissues in situ is used to treat cancer in a manner that ideally minimizes both the potential for damage to healthy tissue and for seeding of the tumor cells. Ablative procedures deliver electromagnetic energy directly to the tumor cells so as to necrose the tumor cells. The tumor cells are not cut, so the incidence of seeding is eliminated. Furthermore, the use of electromagnetic energy can be advantageous, because it can be rapidly dissipated and therefore can reduce the incidence of damage to healthy tissue surrounding the treatment site.
One such electromagnetic energy for use in ablation of tumor cells is radio frequency, or RF, energy. In typical RF ablation procedures, however, it is difficult to position the ablation electrodes so as to ablate effectively the entire tumor mass without resorting to multiple procedures.